Major Common Causes of Blurry Vision in One Eye

DR. AJAY SHARMA February 15, 2025

Have you ever woken up and noticed that one of your eyes feels different, as though the world has suddenly become hazy and unclear? Blurry vision in one eye is a common concern. Many people experience it at some point in their lives, but the reasons behind it can vary widely. Sometimes, it might be something harmless, like eye strain, while in other cases, it could indicate a serious underlying health issue. Understanding the common causes can help you take timely action and protect your vision.

Refractive Errors

One of the most common reasons for blurry vision in one eye is an uncorrected refractive error. This includes:

• Myopia (Nearsightedness): Difficulty seeing distant objects clearly.
• Hyperopia (Farsightedness): Trouble focusing on nearby objects.
• Astigmatism: Uneven curvature of the cornea, causing blurred vision at all distances.
• Presbyopia: Age-related difficulty in reading or seeing close objects clearly.

Now, let’s understand how refractive error occurs, which leads to Blurry vision in one eye. It happens when the shape of the eye, either its length or corneal curvature, does not allow the light to focus correctly on the retina. This can occur due to genetic issues, size and shape issues, injury, cataracts, and lifestyle issues such as high screen time. When your eyeball is too long, you have myopia (short-sightedness); when it is too short, you have hyperopia (farsightedness).

If one eye has a stronger refractive error than the other, you may experience blurriness in that eye alone. Getting an eye check-up and wearing the correct prescription glasses or contact lenses can resolve the issue.

Dry Eye Syndrome

Dry eye occurs when your eyes do not produce enough tears or the quality of tears is poor. This can lead to irritation, discomfort, and blurry vision. Common causes include:

• Excessive screen time
• Air conditioning or pollution
• Aging
• Certain medications
• Autoimmune diseases like Sjögren’s syndrome

Other than the commonly observed causes, there are also some rare causes. They include instability in your film, consisting of lipid, aqueous, and mucin, which can lead to fast tear evaporation. It is also due to the meibomian gland response, where insufficient lipid secretion is responsible for increased tear evaporation. It can also be due to the upkeep of lacrimal gland secretion, in which the aqueous tear generation is diminished. The quality and stability of the tear film are affected when epithelial cells and secretory glands are affected by the inflammatory cytokines.

If a dry eye affects one eye more than the other, it may result in blurriness on that side. Using lubricating eye drops and making lifestyle changes can help relieve symptoms.

Eye Strain and Fatigue

Long hours of reading, working on a computer, or using a smartphone can cause eye strain, leading to blurry vision in one eye. This happens because one eye might be working harder than the other. Resting your eyes, adjusting screen brightness, and following the 20-20-20 rule (taking a 20-second break every 20 minutes and looking at something 20 feet away) can help prevent strain.

Eye Infections

Infections like conjunctivitis (pink eye) or keratitis can cause blurry vision in one eye. Symptoms may include:

• Redness
• Itching or burning
• Discharge
• Sensitivity to light

Bacterial or viral infections need proper medical treatment, so if you suspect an infection, consult an eye specialist.

Cataract

A cataract is the clouding of the eye’s natural lens, leading to blurry vision. While cataracts usually develop in both eyes over time, they may start in one eye first, causing one-sided blurry vision. Cataracts are more common with aging but can also occur due to diabetes, prolonged steroid use, or eye injuries. Surgery is the only effective treatment for cataracts when they start interfering with daily activities.

Glaucoma

Glaucoma is a condition where increased pressure in the eye damages the optic nerve. While it often affects both eyes, it can sometimes start in one eye first. Symptoms include:

• Gradual loss of peripheral vision
• Blurry or foggy vision
• Eye pain or pressure

Since glaucoma can lead to permanent vision loss if untreated, regular eye check-ups are essential, especially for people with a family history of the disease.

There are two types of glaucoma, and both open-angle and closed-angle glaucoma may result in Blurred vision in one eye due to damage to the optic nerve and acute or progressive variations in intraocular pressure (IOP). Because glaucoma can develop asymmetrically, symptoms may first appear in one eye.

Open-Angle Glaucoma

Here’s how it causes blurry vision in one eye.

• Gradual damage to the optic nerve in months or years.
• Loss of peripheral vision first, often unnoticed
• The brain compensates using the healthier eye.
• Finally, it causes mild blurring or dimming in one eye.

Closed-Angle Glaucoma (Acute or Intermittent)

This is how closed-angle glaucoma leads to one-eyed blurred vision.

• Quick IOP surge leads to swelling of the cornea (edema)
• Light scattering causes sudden blurry vision in one eye.
• Optic nerve ischemia can occur within hours.
• Typically affects one eye at a time.

Why One Eye Is Often Affected First?

• Anatomical differences between eyes
• Uneven aqueous humor drainage
• Asymmetrical optic nerve susceptibility
• Variations in blood supply

Retinal Detachment

Retinal detachment occurs when the retina pulls away from the back of the eye. It is a medical emergency and requires immediate treatment. Symptoms include:

• Sudden blurry vision in one eye
• Flashes of light
• A curtain-like shadow over part of your vision
• Increase in floaters (small dark spots in vision)

If you experience these symptoms, visit an eye specialist immediately.

Age-Related Macular Degeneration

Age-related macular degeneration (AMD) affects the central part of the retina, leading to vision loss.

Dry and Wet Age-related Macular Degeneration are the resultant conditions caused by the destruction of the retina, specifically the macula, which is the center of the eye and is responsible for enabling sharp vision and fine details. It leads to blurring of the vision of one eye, particularly during the initial or lopsided stages. The development of Dry AMD is caused by retinal damage associated with aging and by the accumulation of metabolic waste products.

Key Mechanisms of Dry AMD

• Breakdown of Retinal Pigment Epithelium (RPE)
• Drusen Formation
• Oxidative Stress

Key Mechanisms of Wet AMD

• Abnormal Blood Vessel
• Fluid Leakage and Bleeding
• Scar Formation

Why One Eye Is Often Affected First in Age-Related Macular Degeneration?

While it usually occurs in both eyes, early stages can cause blurry vision in one eye. Risk factors include aging, smoking, and a family history of AMD.

• AMD progression can be asymmetrical
• Early damage may occur in one macula before the other
• The brain compensates using the healthier eye until vision loss becomes significant.

Stroke or Mini-Stroke (Transient Ischemic Attack – TIA)

A stroke or mini-stroke can affect the blood supply to the eyes and brain, leading to sudden blurry vision in one eye. Other symptoms may include:

• Weakness or numbness in one side of the body
• Difficulty speaking or understanding speech
• Sudden severe headache

If you suspect a stroke, seek immediate medical attention.

Optic Neuritis

Optic neuritis is inflammation of the optic nerve, often linked to multiple sclerosis (MS). It can cause sudden blurry vision in one eye, along with:

• Pain with eye movement
• Reduced color vision
• Visual field loss

This condition requires medical evaluation to determine the cause and necessary treatment.

Corneal Abrasion or Injury

A scratch or injury to the cornea can lead to blurry vision in one eye. It may occur due to:

• Rubbing the eye forcefully
• Foreign particles like dust or sand
• Contact lens misuse

Minor abrasions heal on their own, but severe injuries may need medical attention.

Migraine with Aura

Some people experience vision disturbances before a migraine attack. This may include:

• Temporary blurry vision
• Zigzag patterns or flashing lights
• Partial vision loss

These symptoms typically resolve after the migraine subsides. If you experience frequent visual disturbances, consult a doctor.

Diabetes and Diabetic Retinopathy

Uncontrolled diabetes can damage the blood vessels in the retina, leading to blurry vision in one or both eyes. Diabetic retinopathy can progress to severe vision loss if left untreated. Regular eye check-ups and blood sugar control are crucial for preventing complications.

High Blood Pressure and Hypertensive Retinopathy

High blood pressure can damage the small blood vessels in the retina, causing blurry vision. In severe cases, it may lead to sudden vision loss. Managing blood pressure through medication, diet, and exercise can help prevent eye problems.

Medication Side Effects

Certain medications, such as antihistamines, antidepressants, and high-dose steroids, can cause temporary blurry vision. If you notice vision problems after starting a new medication, consult your doctor to discuss alternatives.

When to See an Eye Specialist

Blurry vision in one eye should never be ignored, especially if it happens suddenly or is accompanied by other symptoms like pain, headaches, or vision loss. You should consult an eye specialist if:

• The blurriness persists for more than a few hours
• There is sudden vision loss
• You experience flashes of light or floating spots
• You have eye pain or redness
• There is a history of diabetes, high blood pressure, or other health conditions.

Conclusion

Blurry vision in one eye can be caused by various factors, from minor issues like eye strain to serious conditions like retinal detachment or stroke. Early diagnosis and treatment are key to preventing complications. If you or your loved ones are experiencing persistent blurry vision, do not wait for it to worsen.

At Skipper Eye-Q International Eye Hospitals, we provide expert eye care with advanced diagnostic and treatment options. Our experienced specialists can help identify the cause of your blurry vision and recommend the best course of action. Book an appointment today and take the first step toward a clear and healthy vision!